The subject matter of this disclosure is generally related to the medical field. Medical imaging technologies such as stereotactic x-ray, fluoroscopy, computer tomography, ultrasound, nuclear medicine and magnetic resonance imaging enable detection of small abnormalities in the body of a patient. The discovery of certain abnormalities may prompt performance of a biopsy procedure to obtain a tissue sample for lab analysis to help diagnose and treat patients suspected of having cancerous tumors, pre-malignant conditions or other diseases or disorders. The biopsy may be either an open surgical procedure or a percutaneous procedure. Percutaneous biopsy is often preferable to an open surgical biopsy in the case of small abnormalities located deep within the body because a percutaneous biopsy removes a relatively small amount of tissue. For example, a biopsy needle can be used to remove individual cells or clusters of cells in the case of fine needle aspiration (FNA), and a core or fragment of tissue in the case of a core biopsy.
A biopsy gun and guidance system may be used to move the biopsy needle with precision along a planned path in order to obtain a suitable sample of the abnormality. An example of a stereotactic guided lateral arm system is disclosed in U.S. Published Patent Application 2001/0087132 A1, Ser. No. 12/715,591, titled NEEDLE BREAST BIOPSY SYSTEM AND METHOD FOR USE, which is incorporated by reference. In order to perform a biopsy procedure the breast is placed in compression and multiple x-ray images are used to localize the abnormality and perform final adjustments of the needle guidance system. One technological challenge in designing guided biopsy systems is that the biopsy needle may create undesirable artifacts in the images. For example, in a configuration where the biopsy needle is aligned with the path between the x-ray source and x-ray detector a portion of the needle may reside in the path and consequently be imaged. Another technological challenge is accommodation of relatively thin breasts. A “side entry” may be the only practical option for biopsy of a thin breast under compression. The lateral arm may be detached and reattached in order to set up for such a procedure. However, various manual calculations may be required in order to prepare for the procedure and the breast platform or x-ray detector may interfere with the path of the biopsy gun due to space limitations. These technological challenges may become even more complex if tomotactic guidance is used rather than stereotactic guidance. Tomotactic guidance is based on tomosynthesis imaging. A s disclosed in U.S. Published Patent Application 2008/0045833 A1, Ser. No. 11/707,587, titled BREAST BIOPSY AND NEEDLE LOCALIZATION USING TOMOSYNTHESSIS SYSTEMS, which is incorporated by reference, exposures at angles where the biopsy gun would cause artifacts to appear in the image can be skipped. In general, however, a breast biopsy system that would help solve some or all of these challenges would be desirable.